1. Field of the Invention
The present invention relates to an ink composition which can realize recorded images having excellent glossiness and, at the same time, having excellent ozonefastness and rubbing/scratch resistance.
2. Background Art
Ink jet recording is a recording method wherein ink droplets are flied from fine nozzles and are deposited on a recording medium to perform recording. Pigments are sometimes used as a colorant in ink compositions used as inks for ink jet recording from the viewpoint of improving lightfastness and waterfastness. Since such pigment-based ink compositions, however, sometimes only have unsatisfactory fixation onto recording media, various techniques have been developed.
In recent years, there is an increasing demand for higher-grade recorded images. Among others, various proposals have been made for further improving gloss of recorded images.
Further, prints prepared using ink compositions are placed indoors, as well as often outdoors, and, hence, are exposed to sunlight and outdoor air (such as ozone, nitrogen oxide and sulfur oxide). Although pigment-based ink compositions are superior to dye-based ink compositions in lightfastness and gasfastness, the pigment-based ink composition having further improved lightfastness and gasfastness are demanded.
To meet these demands, Japanese Patent Laid-Open No. 162043/2004 proposes the addition of a resin comprising a sulfonic acid group-containing polymer to a pigment-based ink composition. According to the patent publication, the ink composition is excellent in fixation of ink to recording media and glossiness, as well as in lightfastness and ozonefastness.
Japanese Patent Laid-Open No. 162043/2004, however, does not disclose a resin produced by emulsion polymerization of an ethylenically unsaturated monomer in the presence of a reactive emulsifier containing a hydrophilic group, a hydrophobic group and a radical reactive group.